Water mattress support



FIG. 1 is a top plan view of a water mattress support showing my new design, the bottom being plain and unornamented;

FIG. 2 is a enlarged side elevational view thereof, shown broken-away for convenience of illustration and with the sides opposite and adjacent being identical in appearance;

FIG. 3 is an enlarged fragmentary vertical cross-sectional view thereof, taken along line 3--3 of FIG. 1; and

FIG. 4 is an enlarged fragmentary vertical cross-sectional view thereof, taken along line 4--4 of FIG. 1. 

The ornamental design for a water mattress support, as shown and described. 